Won Kil Lee

Comparison of Collagen-coated Polyethylene Terephthalate Disc Plate and Shell Vial Culture Method for the Isolation of Chlamydophila pneumoniae

Background: Chlamydophila pneumoniae is one of the major respiratory infectious pathogens and can be accurately diagnosed by cell culturing. The author performed this study to compare the usefulness of the collagen-coated polyethylene terephthalate (PET) disc culture method and that of the shell vial method. Methods: Twenty-nine sputums and 17 blood specimens collected from 46 patients for C. pneumoniae culture were inoculated into HeLa-229 cell monolayers cultured in shell vials and polyester plates. After incubation, they were stained using the indirect immunofluorescent method with genus-specific FITC-conjugated anti-chlamydia antibody. When both results were inconsistent, microimmunofluorescence results were used. Results: HeLa-229 cells successfully formed monolayers in shell vials and collagen-coated PET plates in all cases. Positive inclusion bodies in HeLa-229 cells of shell vials and PET plates for C. pneumoniae culture were similarly stained with the indirect immunofluorescent method. Both methods showed consistent results with 20 positive and 22 negative cases. The total agreement between the PET plate and shell vial was excellent (91.3%, k=0.826). Conclusion: The collagen-coated PET disc culture method showed highly consistent results with that of the shell vial method, and no technical differences were experienced between the two methods. Therefore, the author concluded that the shell vial method could be replaced by the PET plate method for detection of C. pneumoniae. (Korean J Clin Microbiol 2010;13:73-78)

Dermabacter jinjuensis sp. nov., a novel species of the genus Dermabacter isolated from a clinical specimen.

A Gram-stain-positive, catalase-positive, facultatively anaerobic, non-motile, coryneform bacterium, designated strain 32T, was isolated from a closed pus sample from a patient having finger necrosis in Korea. Strain 32T was considered as representing a novel species according to its initial identification by matrix-assisted laser desorption/ionization-time-of-flight MS. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 32T belonged to the genus Dermabacter and was closely related to Dermabacter hominis DSM 7083T (=ATCC 49369T) (98.34 % similarity). Optimal growth was observed at 30-40 °C and pH 7. Growth occurred in the presence of 0-6 % (w/v) NaCl. Menaquinones MK-8, MK-7 and MK-9 were the major respiratory quinones. The major polar lipids were phosphatidylethanolamine, phosphatidylcholine, glycolipid and two unknown lipids. The major cellular fatty acids were anteiso-C17 : 0, anteiso-C15 : 0, iso-C16 : 0 and iso-C15 : 0. The DNA G+C content of strain 32T was 62.58 mol%, and the mean level of DNA-DNA relatedness between strain 32T and D. hominis ATCC 49369T was 49±1.6 %. Based on the phenotypic and genotypic characteristics, strain 32T is confirmed to represent a novel species of the genus Dermabacter, for which the name Dermabacter jinjuensis sp. nov. is proposed. The type strain is 32T (=NCCP 16133T=DSM 101003T).

Novel influenza A (H1N1) infection in immunocompromised patients

BACKGROUND Since April 2009, novel influenza A (H1N1) infection is spreading throughout the world. This infection might be fatal for immunocompromised patients who are at a potentially high risk of developing infectious complications. We investigated the detection rate and features of H1N1 infection in immunocompromised patients. METHODS Between August 2009 and February 2010, we examined 8,112 subjects, including 390 immunocompromised patients, for H1N1. Swab samples were taken from the nose and throat of the participants. Real-time PCR was performed to identify H1N1 viral genes. RESULTS Positive results were obtained in 2,953/8,112 (36.4%) subjects and 46/390 (11.8%) immunocompromised patients. H1N1 was identified in 8.7% patients with solid cancer, 12.9% patients with hematologic malignancy, 16.7% patients with chronic renal disease, and 14.5% patients with kidney transplantation. The mean cycle threshold (Ct) value of PCR was significantly lower (P<0.05) in patients with hematologic malignancy as compared to that in patients with chronic renal disease and control subjects. Four patients died due to respiratory complications. CONCLUSIONS The detection rate of H1N1 was significantly lower in immunocompromised patients than in other patients. The Ct value of patients with hematologic malignancy was significantly lower than that of other immunocompromised patients and control subjects.